Non destructive folding/unfolding (ie, no insertion of whitespace in unfolding)

Hello list,

This is my first post, so I apologise if this has already been
covered.  I searched through the full text archive file of ietf-822
(after going through the full itef-smtp archive file) and could not
find a concrete answer to my question.

I am improving/fixing bugs in a Email library for Ruby - I didn't
originally write the library, so I am being very careful in any
changes I make.

One situation I have is where a X-header field and Reply-To field has
a single piece of text that is longer than the 78 octet limit, but has
no white space break.

For example:

Reply-To: <1234-1234-1234-1234-1234-1234-1234-1234-1234@me-some-host-over-here.org>

The library currently folds this line as:

Reply-To:CRLF
LWSP<1234-1234-1234-1234...blah-with-no-further-fold

Now, I have two questions.

1) I believe that putting the CRLF immediately after the : in the
header field name is in violation of 2822 specifically that the header
line should contain the name, a colon, the field and terminated by a
CRLF.  Would this be a correct interpretation?

2) Irregardless of (1), what is the correct handling of a piece of
text in the field that is longer than 78 characters, but contains no
whitespace to fold?  ie, in unfolding, no whitespace can be inserted
back into the original text which would be destructive to the original
text.

I saw one mention of doing this:

Reply-To: <1234-1234-1234-1234-1234-12\CRLF
LWSP34-1234-1234-1234

But I can not find this in the RFC 2822 and my library breaks on this
when it tries to unfold, so I am not sure if my library's unfolding
function is at fault or if my folding implementation is incorrect.

If I have missed something obvious, I apologise.

Regards

Mikel